.TH "sane\-rts8891" "5" "8 Dec 2008" "@PACKAGEVERSION@" "SANE Scanner Access Now Easy"
.SH "NAME"
sane\-rts8891 \- SANE backend for rts8891 based scanners
.SH "DESCRIPTION"
The
.B sane\-rts8891
library implements a SANE (Scanner Access Now Easy) backend that
provides access to scanners based on the rts8891 ASIC.
.PP 
The scanners that work with this backend are:
.PP 
.RS
.ft CR
.nf 
   Vendor Model           status
\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-  \-\-\-\-\-\-\-\-\-\-\-
  Umax Astra 4400       untested
  Umax Astra 4450       untested
  HP scanjet 4000c      good
  HP scanjet 4470c      good
.fi 
.ft R
.RE

The options the backend supports can either be selected through
command line options to programs like scanimage or through GUI
elements in xscanimage or xsane.

.br 
If you have any strange behavior, please report to the backend
maintainer or to the SANE mailing list.

Valid command line options and their syntax can be listed by using 
.RS
scanimage \-\-help \-d rts8891
.RE

.TP 
.B Scan Mode Options

.TP 
.B \-\-mode
selects the basic mode of operation of the scanner valid choices are 
.I R Color ,
.I Gray
and
.I Lineart
The default mode is Color. The Lineart mode is black and white only (1 bit). 
Grayscale will produce 256 levels of gray (8 bits). Color mode allows for over
16 million different colors produced from 24 bits of color information.

.TP 
.B \-\-resolution
selects the resolution for a scan. The horizontal and vertical resolutions are set 
by the value of this option. The scanner is capable of the following resolutions for the specified option value:
.PP 
.RS
.ft CR
.nf 
  Value   Hor. Resolution  Vert. Resolution 
  \-\-\-\-\-   \-\-\-\-\-\-\-\-\-\-\-\-\-\-\-  \-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-
  75      75dpi            75dpi
  150     150dpi           150dpi 
  300     300dpi           300dpi 
  600     600dpi           600dpi 
  1200    1200dpi          1200dpi
.fi 
.ft R
.RE

.TP 
.B \-\-preview
requests a preview scan. The resolution used for that scan is 75 dpi
and the scan area and the scan mode are as specified through their options, 
or the default if not specified. The default value for preview mode is "no".

.TP 
.B \-\-threshold
selects the  minimum\-brightness to get a white point. The threshold is only used with Lineart mode scans.
It is specified as a percentage in the range 0..100% (in steps of 1).  
The default value of the threshold option is 50.


.SH "CONFIGURATION FILE"
The configuration file
.B @CONFIGDIR@/rts8891.conf
contains the usb device ids of supported scanners (eg usb 0x043d 0x007c) and scanner configuration options.
Empty lines and lines starting with a hash mark (#) are
ignored.
.PP 
The options supported are
.B allowsharing
,
.B modelnumber 
.

Option
.PP
.B allowsharing
enables or not the sharing of the scanner between multiple frontends at the same time.
.PP
.B modelnumber
is used to force the reported model by the backend and is only useful in the case of a scanner which NVRAM has been erased.
.RS
.ft CR
.nf 
0 to report a HP4470c.
1 to report a HP4400c.
2 to report an Astra 4400.
.fi 
.ft R
.RE

.PP 
.SH "FILES"
.TP 
.I @LIBDIR@/libsane\-rts8891.a
The static library implementing this backend.
.TP 
.I @LIBDIR@/libsane\-rts8891.so
The shared library implementing this backend (present on systems that
support dynamic loading).


.SH "ENVIRONMENT"
.TP 
.B SANE_DEBUG_RTS8891 SANE_DEBUG_RTS8891_LOW SANE_DEBUG_RTS88XX_LIB
If the library was compiled with debug support enabled, these
environment variables controls the debug level for this backend. E.g.,
a value of 255 requests all debug output to be printed. Smaller levels
reduce verbosity.


.SH "LIMITATIONS"
Scanners of the same model exist with different sensors, due to lack of data
(ie USB logs) some sensors are better supported than others. At least 75 dpi
mode is working for any model. Sharing the scanner between several frontends
at the same time (allowsharing option) may not work on some USB controllers.
.PP
XPA is no (yet) supported.
.SH "BUGS"
.br 
No bugs currently known.


.SH "SEE ALSO"
sane\-scsi(5), scanimage(1), xscanimage(1), xsane(1), sane(7)


.SH "AUTHOR"
.TP 
This backend has been developed by St\['e]phane Voltz.
.I http://stef.dev.free.fr/sane/rts8891
.SH "CREDITS"
.TP 
Many thanks go to:
Laurent Fournier who donated me a HP4470c.
Vladimir Sysoev and "TheUnruly Squash" for the time they spent recording
USB activity and testing the experimental version on HP4400 models.
